The amount of information stored on personal computer systems is enormous and rapidly expanding. Some file systems use hierarchical organization to store computer files. Files are named and placed in a directory. The number of files, however, can easily exceed thousands or tens of thousands. Searching and locating specific files can be quite challenging.
Content-based search tools are used to locate files on a computer system. A user enters a keyword or words, and the tool searches given files for the occurrence of the keyword. The tool then displays the search results to the user.
Content-based searches provide a simple search tool, but are not effective for many types of searches. For example, a user might forget an important keyword or search for a file that does not contain the keyword entered in the search query. In other instances, some files, such as images, are not searchable with keywords since these files do not contain text.
In view of the large amount of files and data stored on computer systems, users need effective tools for organizing and searching such files.